Means and method of conserving heat in milk driers



Sept. 16, 1930. c, c, s w Er AL 1,776,030

MEANS AND METHOD OF CONSERVING HEAT IN MILK DRIERS Filed May 10, 1929 3 Sheets-Sheet 1 BOILER MILK STURAGE PREss URE AEDUCER M/LK HEATER M/LK 02/52 Sept. 16, 1930. c, s w ET AL 1,776,030

MEANS AND METHOD OF CONSERVING HEAT IN MILK DRIERS Filed May 10, 1929 3 Sheets-Sheet 2 cfiesier C/(ersZaw flaroll L. 50};

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flrcom s Sept. 16, 1930. c. c. KERSHAW ET AL 1,776,030

MEANS AND METHOD OF CONSERVING HEAT IN MILK DRIERS Filed May 10, 1929 3 Sheets-Sheet 3 Swank (.5

i fifiesier cl/ferslawf/arabi L.8qlzle firm H2114 Patented Sept. 16, 1930 UNITED STATES PATENT OFFICE CHESTER C. KEBSHAW, OF ST. PAUL, AND HAROLD L. SOLIE, 0F MINNEAPOLIS, MINNE- SOTA Application fi1ed May 10, 1929. Serial No. 361,952.

In milk drying plants of thetype in common use the milk is delivered to the outer periphery of cylindrical driers which are heated from within by steam under pressuresas high as about 95 pounds per square inch. This invention relates particularly, although not exclusively, to the utilization of the condensate from sucn driers to preheat the milk and to generally improve the eiflciency of the plant.

The difiiculties attendant upon the use of the condensate to preheat the milk have been such that many of the milk drying plants have heretofore wasted a large part of the heat in the condensate. One of the chief difliculties is that the condensate at a high 7 temperature (often above 300 F.) when brought in contact with pipes or other containers of the milk causes the milk to solidify and adhere or cook on to the hot surfaces, thus clogging the passages and burning the product. Heretofore, it has been common practice to allow the exhaust from the condensate traps to merely pass off into the atmosphere.

7 It is our object to utilize the heat thus wasted to preheat the milk in a manner which avoids the solidification and scorching of the milk and requires only simple and inexpensive v apparatus.

In the accompanying drawings we have illustrated the best form of our invention at present known to us. Referring to the drawings, Figure 1 is a diagrammatic end view of a drier of common type; Fig. 2 is a diagrammatic side elevation of the same showing our improved heat conserving means connected thereto; Fig. 3 is an enlarged side elevation of the principal parts of our improved apparatus, partially in central vertical section; Fig. 4 is a transverse section through the milk heater taken on the line 44 of Fig. 3'; Fig. 5 is an end elevation of the apparatus as viewed from the left of Fig. 3; Fig. 6. is an elevation as viewed from the right of Fig. 3, and Fig. 7 is a central vertical section through a suitable trap for use in connection with our invention.

The drier shown diagrammatically in the drawings has a pair of cylinders 7 which are rotated in the direction indicated by arrows in Fig. 1 and heated by steam supplied under pressure through pipes 8 in well known manner. Theperipheries of the cyl-. mders 7 are disposed in close proximity to each other so that a trough is formed between them into which the milk to be dried is delivered by a pipe 9. A film of milk adheres tothe lower periphery of the cylinders 7 and as they rotate this film dries and is" removed from the periphery by longitudinally disposed scrapers 10, the dry material falling into suitable troughs 11 and being carried out of the driers by suitable conveyors 12 located in the bottom of the" trough 11. Vapor rising from the drier is collected in a suitable hood 7? and conducted away therefrom.

A condensate withdrawal pipe 13 com- ,7 municates with the interior of each of the cylinders 7 and conducts the condensate to a suitable trap 14. Details of a suitable trap are shown in Fig. 7 The pipe 13 communicates with the bottom of the trap and the pipe The the inlet opening from the pipe 13 and motion is transmitted from the float 41 to the clo sure 40 through levers 42 and 43 which are pivotally supported 011 the lower ends of rigid bracket arms 44 and45, respectively.

A link 46 connects the lever 42 with the lever 43 so that when the float 41 rises the closure 40 is moved to closed position, otherwise water may flow from the pipe 13 past the open closure 40 to the pipe .15. In the normal operation of the drier steam is delivered intermittently to the trap 14 and when a quantity of steam is received in the trap it displaces the water in the float 41 and causes said float to rise with the result that the pipe 15 is closed until the steam is condensed or escapes when the outlet passage again opens by the falling of the float. A small vent 4. is provided in the top of the float 41 to permit the gradual escape of air or steam therefrom. From the traps 14 a pipe 15 is 'agetank 28 (Fig.2).

"arranged to transmit condensate to our improved apparatus for utilizing the heat therein to preheatthe milk supplied tothe pipe The pipe delivers the condensate at the high pressure of the cylinders 7 to a pressure reducing tank 16 fwh'ere the sudden 'fall of the pressure causes a substantial part a of the condensate tofiash into steam. This tank 16 isjof stout" construction @adapted .to withstand the sudden pulsations caused the vintermittent delivery of the condensate from the trapslt. Asaprecautionarymeasure, to eliminate danger in case of ,a'stoppage in the outlet connectionsr'apressure re lief valve 17 is provided on the tank 16.

An outlet "pipe f1'8iconnnunicates 'fit' ith the lower partfdf'theftank' lfi at one' end and connects with a distrib'utingpip'e 19 extend ing axiallyfwithinla'milk'heater having a V casing 20. Withingthe *cylindri'cal outer *cas'ing20-is acoil 21' through. which. milk is 1 forced a pump 22 (Fig; 2). Connecting 'the coi'l Ql'xviththe-pump is ia pipe 23, f The ..'several' "sectionsfof the coil 21, extend- "ing within the heat'encasing 2( are joined together (in 'a continuousfconduit U- shaped. connections '24; projecting fromi the ends of thecasing 20. fThe outlet from the coilQlcOmprises a pipe 25 having a valved branch f26 l communicating with the pipe 9, -and'another"branch 27 constituting an over- How to return'anv excess of milk-'to'a stor- The outlet from thecasing 2O 'foricondensate comprises a pipe :29 communicating with the bottomofthe casingQO and extendin'g upward to a point above or about at the topr'of, the casing, 20 wherefit passes to a 'boiler feed pump 30 iorfother place of dis posal for the condensate. 'A'check valve 29 is provided to prevent flow back into the casing 20 through thepip'e'29. To prevent the trapping of "air, steam' or the like within the casingl2O .a'ivent pipe ,3liis 'connected to the topf'of the Casing 2 Valid has a branch 32 communicating with the-condensate deliveryfpipe 29 'A'sec'ond branch 33 ofthe pipe 31 has a risingportion and thenextends downward to waste. the excess condensate in" the eventi-that it is formed more rapidly than itis drawnloii from the pipe 29. One'of the important features of our in: "vention' is the arrangementfor so distributing thelfiuid' from the pipe 19 that itdoes s v I claimas 'new 'an'd desire to protectby Let-ters i i not impinge directly on the pipes-ofthecoil 2 1 i As best shown in Figs; 3'and 4, thedisdensate 'andsteam at substantially atmosflpheric pressure between the severalpipes ot;

the coil 21 as indicated by 'arrowsinFig.

,4. In the'absence of such arrangement; the fluid from the pipe 19; which is at -temperatu'res ranging from about 21 O degrees Fah-' -o :renheit to about 220 degrees Fahrenheit,

gwould be apt to -cause -the mil-k thecoil 21 to adhere atthe points or impingement and 36' to' 'e 's e' tt e t kjl i a d a c eef 's membersf38 aflordingsuppo-rts T for the"; Gas- In the operationof eurQapparatusythe 1-pipe 1 5 delivers condensatefi intermittently V from the trap s lleto the tank 16 where the pressure otabo'ut to Ijp'ounds per; square 5 inch .uponf'the fluid is), reducedg substantially flashes into steam. or The sensible heat inthe" c vcondensateand latent he'atIotthe steamsd o fQ-BII IB dliSWlltlllztld tQfhflfitthfi lllllkipaSsr c I ing throiiigh the soil :21. Thus ?the; pipesj18 ,and- 19 draw. of? the stea'm and condensate {from the tank 16' and the openingsf34 in the pipe 19 so distributethefhotjfluid that it [does not directly impingeagainstthe. co-i l21 I g biut iscircu-lated between thepipes. The casing 20 is maintained substantially-filled J condensate by ourarrangement of the withfdrawal'pipe 29-;which trapsf-thewaterd-in ,vthecasing,.wTheflvent pipe' 31fprevents the 7 accumulation, or trapping", 01E airv I or steam within the casing 20.. The; pump 22 contin- I 'uouslyqsupplies the dryingfcylindersi with 7 milk through theapipe 23, "coil'21 and pipes i-than 212 degrees'Fahrenheit; i

Patent is I tions 34, therein Which direct'streamsofcon n 7 5 5 I gradually collect causingthe)objectionable; T cooking'oni ofthe milk-andlultimate dog I 7 ging or stoppage of the coils 21. 7 To facilitate'iemptying the-casing 20 a valvedjbi anchfie is provided You the pipe f29,as"shownfinc Standards 36' aif0r'd o suitable supports for v the-tank 16, casing; 20 1 r i "and connections, suitablefbrackets 37." being r secured'on otheupper endsiof the standards p ph 'ifi 3 ap rt Ofthe condensat o 25,26 and9, the flow fromzth'e latterzpipe {being controlledby a valve;-26 v 'We-have foundintopra'ctice that'our invention operates l successfully to conserve the; greater part ofjthe heat in" the; conden- I sate which has: heretofore been :wa-sted,r the heat thus'saved being utilized 'to'increasethe rate ofxdrying of the' mi'lk to agsubstantial' degree. 2 I I Itistobe understoodthatthei expression I about 212 degrees Fahrenheit in thewfol= lowing claims is intended to) include varia- 1 tions of approximately-5%; more I or less i 6i? tributing pipe 19 "'has'a number of per-for'aj in 1a The "combination tvithiaizmflk etish smr15 ploying steam at temperatures above 212 degrees Fahrenheit, of apparatus for utilizing the condensate from said drier to preheat the milk, comprising an expansion tank, a milk heater, connections for transmitting the condensate from the drier successively to said expansion tank and to said heater, said tank being adapted to reduce the temperature of said condensate to about 212 degrees Fahrenheit and to allow the formation of steam therefrom, and means for passing the milk through said heater to the drier to utilize the latent heat in the stream formed in said ex- .mation of steam therefrom, means in said heater for distributing the steam delivered thereto to prevent solidification of the milk therein and means for passing the milk through said heater to the drier to utilize the latent heat in the steam formed in said expansion tank.

3. The combination with a milk drier employing steam under pressure, of apparatus for utilizing the condensate from said drier to preheat the milk, comprising an expansion tank, a milk heater, said heater having a coil for milk, connections for transmitting the condensate from the drier successively to said expansion tank and heater, said tank being adapted to reduce the pressure and temperature of the condensate and allow the formation of steam therefrom, and means for passing the milk through said coils into the drier to utilize the latent heat in said steam formed the fluid between the coils, means for maintaining said casing substantially filled with condensate and means for passing the milk through said coil into the drier to utilize the latent heat in the steam formed in said expansion tank.

o. The combination with a milk drier employing steam under pressures substantially above atmospheric pressure, of apparatus for utilizing the condensate from said drier to preheat the milk, comprising an expansion tank, a milk heater having a cylindrical casing and a coil in said casing, connections for transmitting the condensate from the drier successively to said expansion tank and casing of the heater, said tank being adapted to reduce the pressure of said condensate to about atmospheric pressure and to allow the formation of steam therefrom and distributing means for the condensate within said heater adapted to direct the fluid between the coils, said means having a perforated pipe extending axially in said casing, and means for passing the milk through said coils into the drier to utilize the latent heat in the steam formed in said expansion tank.

6. The method of conserving heat in milk driers or the like employing steam at pressures substantially above atmospheric, and having a coil for preheating the fluid to be dried, which consists in withdrawing the condensate from the drier, reducing the pressure and temperature of said condensate to form steam and utilizing the latent heat in said steam by circulating said steam and the remaining condensate about said coil to preheat said fiuid preparatory to drying the same while distributing said steam about said coil to prevent local solidification of the contents of said coil.

7 The method of conserving heat in milk driers or the like employing steam at pres sures substantially above atmospheric, and having a coil for preheating the fluid to be dried, which consists in withdrawing the condensate from the drier, reducing the pressure and temperature of said condensate to form steam and circulating said steam and the remaining condensate about said coil to preheat said fluid preparatory to drying the same, while maintaining said coil submerged in the condensate.

In testimony whereof, we have hereunto signed our names to this specification.

CHESTER. C. KERSHA'W. HAROLD L. SOLIE. 

